Materials and structures for nonlinear photonics

In this chapter we summarize progress in materials and structures for all-optical signal processing that employ either the second or third order optical nonlinearity. Three-wave mixing and cascading in periodically-poled lithium niobate waveguides dominates signal processing in second order materials. In the case of third-order nonlinearities, four wave mixing is the dominant physical process but here the range of materials that have been employed is wider and ranges from glasses to both active and passive semiconductor devices. This chapter provides a brief summary of the advantages and disadvantages of each class of materials and device structure as well as the state-of-the-art for each case.